This invention relates to a system for monitoring broadcast channels, and in particular to a centralized system that permits a user to remotely query multiple broadcast channels for program content of interest.
Our co-pending application no. PCT/CA96/00131 describes an automatic broadcast monitoring system that allows a user to automatically monitor TV channels on a PC equipped with a video card. The system includes a search engine that allows the user to input selected keywords. The search engine continually monitors the closed caption stream accompanying the broadcast material to find a keyword match and identify program material of interest to the user.
While this system offers an extremely powerful search facility, it ties up resources in the user""s PC on an on-going basis as it looks for a match. It also consumes considerable bandwidth to the user""s location since the PC must continually receive the broadcast channels in order to monitor them.
An object of the invention is to alleviate this disadvantage.
According to the present invention there is provided a system for monitoring broadcast channels, comprising means for receiving a plurality of broadcast channels; a central search server operable to search said broadcast channels for a match with pre-stored profiles; a channel server associated with each broadcast channel for deriving therefrom a dynamically changing data stream that is representative of, and changes with, the current content of the associated broadcast channel, said channel server providing said data stream to said search server for matching with said pre-stored profiles; a memory connected to said search engine for storing said profiles; a plurality of user terminals connected to said search engine over a network, said search engine being responsive to commands from said user terminals to store said profiles in said memory in association with the identity of the user terminal from which a said command was received; and means for sending an alert signal over said network when a match is found with a said pre-stored profile to the user terminal associated with said pre-stored profile, said alert signal identifying the broadcast channel matching the pre-stored profile.
The broadcast channels will normally be television channels, although the invention is applicable to other broadcast media intended for mass distribution, such as radio channels.
The user terminals are conveniently PCs equipped with software for displaying video received in digital form. In accordance with the invention, the PCs can send instructions to the central search engine. This operation only requires a very small amount of bandwidth. The search engine then carries out the monitoring function for a large number of users, for example, on a subscription basis, and only contacts the users when a match is found.
The invention is particularly well suited for Internet applications, although it can also be used over intranets and local area networks.
Many broadcast stations are planning to multicast or unicast over the Internet, so the alert signal can include the Internet address of a program source to enable this to be connected directly to the requesting user. Alternatively, the system can supply the broadcast material to the Internet or other network through servers, in which case the alert signal will include the address of the appropriate system server.
The invention thus avoids the need to send bandwidth intensive broadcast signals to the user from the search engine, nor for the user to receive unwanted broadcast signals.
It is expected in the future that many users will receive xe2x80x9cbroadcastxe2x80x9d channels via the Internet. Such dissemination of material, where there are a finite number of connected user is usually referred to as xe2x80x9cmulticastingxe2x80x9d, but in this specification the term xe2x80x9cbroadcastingxe2x80x9d is used to include xe2x80x9cmulticastingxe2x80x9d. In the case of signals broadcast over the Internet, the invention has the capability of substantially reducing the amount of bandwidth consumed.
As described in our co-pending application, the pre-stored profiles are conveniently keywords that are compared to the closed caption stream associated with the broadcast signals, although other forms of pattern recognition can be used as the technology becomes available.
The invention also provides a method of monitoring broadcast channels from a central location for a plurality of distributed users, comprising the steps of receiving a plurality of broadcast channels at a central location; responding to commands over a network from distributed user terminals to store profiles specifying search criteria at said central location; deriving a dynamically changing data stream from each said broadcast channel for matching with said pre-stored profiles, said data stream being representative of, and changing with, the current content of the associated broadcast channel; continually searching said data stream for a match with said pre-stored profiles; and sending an alert signal over said network when a match is found with a said pre-stored profile to the user terminal associated with said pre-stored profile, said alert signal identifying the broadcast channel matching the pre-stored profile.